Collapsible plastic bags are often used to store liquid products such as chemicals, soft drink syrup, fruit juices and food condiments. The plastic bags are typically housed in a corrugated paperboard box to aid in the transporting, handling and dispensing of the product. Such packaging systems are commonly referred to as “bag-in-box” packaging systems.
The plastic bags typically have sidewalls sealed along a peripheral seam to define a fluid containing chamber. A spout or a fitment provides access to the fluid chamber for filling and dispensing the product within the bag. Vacuum pump systems are sometimes connected to the container to assist in draining fluid from the container. Both gravity dispensing bags and vacuum pump systems suffer from the common drawback that fluid may become trapped within the folds of the bag during draining. Because of this, evacuation channels are often placed within the bag. Evacuation channels are typically elongate cylindrical tubes or flat strips with protruding ribs defining grooves. Typically, one end of the evacuation channel is disposed transverse to, or is connected to the spout, and the other end of the evacuation channel extends into the fluid containing chamber of the bag. As the bag is emptied by the force of the vacuum pump, or by the force of gravity, portions of the bag collapse unevenly, tending to leave pockets of product, typically liquid, which may become isolated from the rest of the liquid in the container. The evacuation channel, however, forms a conduit which cannot be closed off by the folds created in the bag. In this manner the entire chamber of the flexible bag remains in communication with the spout at all times during the dispensing such that all product within the bag can be removed.
Prior attempts to provide such bags are disclosed in U.S. Pat. Nos. 4,601,410; 5,647,511 and 5,749,493. U.S. Pat. Nos. 4,601,410 and 5,647,511 disclose a liquid container with an evacuation unit. In both the '410 and '511 patents, the evacuation unit is shown attached directly to the spout by a mounting ring. Several problems have been encountered with these types of evacuation units. For example, during the filling process, which is typically done in a high speed and high pressure process, the evacuation unit is susceptible of being dislodged from the spout thereby rendering the evacuation unit inoperative. Also, the attaching ring can impede the flow of liquid during the filling process thereby slowing the filling process.
U.S. Pat. No. 5,749,493 discloses an evacuation unit positioned within a bag and transverse and perpendicular to a spout in the bag. Because the evacuation unit is positioned in a location that is in line with the incoming fluid during the filling process, it is susceptible of being dislodged from its mounting to the container thereby rendering it ineffective. The '493 Patent also discloses extruding a pair of ribs or a single rib or protuberance extending the length of the container.
Many of the designs which utilize an evacuation unit positioned within the bag require that the unit be placed into the bag after the bag has been substantially constructed. This is undesirable because it adds another step to the manufacturing process and increases the labor costs.
U.S. Pat. No. Re. 34,929 discloses a plastic bag having interconnected air channels on its inner surface for the vacuum packaging of perishable items. The air channels are formed by the spaces between a plurality of raised protuberances having uniform thickness and formed in a generally regular and waffle-like pattern. The protuberances prevent the total collapse of the bag during air evacuation. There is no disclosure to utilize a fitment to provide access to the contents of the container. There is also no disclosure of removing the stored contents of the bag, but, rather only discloses moving air from the package to prevent spoilage of the perishable item contained therein.
U.S. Pat. No. 2,778,171 discloses the production of air-tight packages for packaging perishable items such as food. Projections are provided near an opening of the airtight package for keeping sidewalls of the container from fully collapsing against one another while air is being evacuated from the container. There is no disclosure of evacuating a stored product from the container and no disclosure of providing a fitment with the bag to provide access to the stored contents.
U.S. Pat. No. 5,728,086 discloses a flexible container having multiple access ports and particularly discloses a container for storing fluids for parenteral administration to a patient. An inner surface of a sidewall of the container can have various patterns embossed thereon to assist in draining the contents of the container.
U.S. Pat. No. 5,928,762 discloses a laminate of a base film and an embossed sheet and a method for fabricating the same. The method includes the steps of joining a base sheet to a molten sheet material. The molten sheet material is cooled and solidified using a cooling roll having embossing patterns in its surface. The method includes the steps of embossing the molten sheet and simultaneously laminating the molten sheet with the base sheet. In an alternative method, an adhesive resin is coextruded on the side of the molten sheet facing the base material. There is no disclosure in the '762 Patent of utilizing more than a single preformed sheet material to fabricate a layered polymeric structure.